Non-medicated starter won't hurt them.
Medicated feed has a thiamine blocker to prevent coccidiosis and shouldn't be used.
Many feed stores will carry both med and non-med starter as well as grower, finisher and layer feed. I've known stores that only carry medicated starter and layer. In that case, try to find another store or ask if they'll order something else.
Other than subtle differences in the nutrient balance, the primary differences in the above feeds are calcium and protein levels.
Starter and grower have higher protein to support growth of young birds. Finisher has lower protein (about 15%) for birds that have nearly reached adult size. Starter, grower and finisher all have about 1% calcium which is all that is needed for birds not producing egg shells every day.
For pullets and hens in production, a layer feed contains approximately 4% calcium, much higher than should be consumed by birds not building egg shells that contain 1.7 grams of calcium.